\begin{tikzpicture}
    \node (表达式) at (0,0) {表达式};
    \node[anchor=west] (项) at ([xshift=2em]表达式.east) {项};
    \node[anchor=west] (因式) at ([xshift=2em]项.east) {因式};
    \node (表达式2) at ([xshift=2em,yshift=-1.5em]项) {(表达式)};
    \draw [->] (表达式.east)--(项.west);
    \draw [->] (项.east)--(因式.west);
    \draw [] (因式.east) -- ([xshift=2em]因式.east) |- (表达式2.east);
    \draw [->] (表达式2.west) -| ([xshift=1em,yshift=-0.3em]表达式.east);
\end{tikzpicture}